Abstract: In order to obtain matrix attachment regions(MARs) from woody plants,calli of Populus nigra were induced from young leaves,and suspension cultured cells were prepared from the calli and used as starting materials for MARs isolation.The nuclei were released after digestion of the cells with pectinase and cellulase,and nuclear matrixes were obtained after removal of the non-MARs segments.Separation of residual DNA and proteins were further performed by employing a high saline buffer,and the residual DNA was recovered and cloned.Two DNA fragments named A7 and A23 with typical MARs characteristics were obtained.Sequence analysis showed that both of the two isolated DNA fragments have the cha-racteristic motifs of MARs.Comparison with other known MARs sequences suggested that these two fragments were two new MARs isolated from Populus,and their functions were also predicted.To our know-ledge,this is the first report of MARs isolated from a woody plant.